Character: Sodium hydrogen difluoride is a colorless or white crystal with relative density of 2.08. It has strong sourness. It is soluble in water, but insoluble in alcohol. In humidity air, sodium hydrogen difluoride can absorb moisture and releases hydrogen fluoride. When heated to 160 ℃, it decomposes into sodium fluoride and hydrogen fluoride. At high temperature aluminium and aluminium alloy can resist the corrosion of hydrogen fluoride. Its aqueous solution can etch glass. It is toxic.

Uses: Sodium hydrogen difluoride is used as aseptic of food, animal specimen and dissection specimen, as glass etchant, in glass frosting, for texture finishing of textile, in wiping off rust, in insect proof treatment of leather, as the material for tinplate, and to produce anhydrous HF. Its mixture with potassium hydrogen fluoride can be used as flux of metal.